Re: [PATCH] manual: Drop incorrect statement on PIPE_BUF and blocking writes

["Štěpán Němec" <stepnem@smrk.net>]

On Mon, 25 Mar 2024 12:46:47 +0100
Florian Weimer wrote:

> * Štěpán Němec:
>
>> diff --git a/manual/pipe.texi b/manual/pipe.texi
>> index 483c40c5c3dd..8a9a275cafe7 100644
>> --- a/manual/pipe.texi
>> +++ b/manual/pipe.texi
>> @@ -312,8 +312,7 @@
>>  
>>  Reading or writing a larger amount of data may not be atomic; for
>>  example, output data from other processes sharing the descriptor may be
>> -interspersed.  Also, once @code{PIPE_BUF} characters have been written,
>> -further writes will block until some characters are read.
>> +interspersed.
>
> Maybe “further may block” instead?  I think the reference to PIPE_BUF
> and blocking could still be helpful, except that it's not a guarantee,
> as you correctly point out.

(Assuming you meant “further writes may block”, i.e., just
s/will/may/ in the pre-patch text.)

Ignoring the fact that the sentence seems simply wrong, at
least in environments where the vast majority of glibc
installations run (Linux with the relevant parameters as
described in my commit message), I don't find the sentence
particularly helpful, as the section focuses on _atomicity_,
not blocking, so I find the sudden side note on blocking
somewhat out of place here in any case.

And as for your particular suggestion (if I understood it
correctly), I would find that formulation _very_ unhelpful,
unless supplemented by additional details (i.e., under what
conditions "may" the blocking happen; but again, why talk
about this at all in a section titled "Pipe Atomicity"?).

> Do you have copyright assignment?

I do not, and I thought it wasn't necessary for this kind of
change.

> If not, please add Signed-off-by: in a second submission
> of the patch.

Will do (if the result of the discussion calls for it, i.e.,
some version of my patch turns out acceptable).

Thanks,

  Štěpán